In general, an airbag for a front passenger seat is installed in an instrument panel that is disposed at an upper side of a glove box.
The airbag for a front passenger seat tears an upper skin of the instrument panel while being inflated by gas generated by a gas generator, protrudes upward from the instrument panel, and then is deployed forward toward an occupant.
When the airbag for a front passenger seat is deployed forward toward the occupant, the airbag is deployed while falling downward from an upper side of the instrument panel. Therefore, while the airbag for a front passenger seat is deployed, the airbag rebounds upward again by pressure of gas in the airbag.
When the head of the occupant comes into contact with the airbag for a front passenger seat at a point of time at which the airbag for a front passenger seat rebounds as described above, the head of the occupant is tilted backward due to rebounding airbag, and as a result, the neck of the occupant is injured.